Commit | Line | Data |
---|---|---|
af558e33 BF |
1 | /* |
2 | * Common code for control of lockd and nfsv4 grace periods. | |
f7790029 JL |
3 | * |
4 | * Transplanted from lockd code | |
af558e33 BF |
5 | */ |
6 | ||
7 | #include <linux/module.h> | |
db9c4553 | 8 | #include <net/net_namespace.h> |
f7790029 JL |
9 | #include <net/netns/generic.h> |
10 | #include <linux/fs.h> | |
db9c4553 | 11 | |
c7d03a00 | 12 | static unsigned int grace_net_id; |
af558e33 BF |
13 | static DEFINE_SPINLOCK(grace_lock); |
14 | ||
15 | /** | |
16 | * locks_start_grace | |
f7790029 | 17 | * @net: net namespace that this lock manager belongs to |
af558e33 BF |
18 | * @lm: who this grace period is for |
19 | * | |
20 | * A grace period is a period during which locks should not be given | |
21 | * out. Currently grace periods are only enforced by the two lock | |
22 | * managers (lockd and nfsd), using the locks_in_grace() function to | |
23 | * check when they are in a grace period. | |
24 | * | |
25 | * This function is called to start a grace period. | |
26 | */ | |
f7790029 JL |
27 | void |
28 | locks_start_grace(struct net *net, struct lock_manager *lm) | |
af558e33 | 29 | { |
f7790029 | 30 | struct list_head *grace_list = net_generic(net, grace_net_id); |
db9c4553 | 31 | |
af558e33 | 32 | spin_lock(&grace_lock); |
81833de1 VA |
33 | if (list_empty(&lm->list)) |
34 | list_add(&lm->list, grace_list); | |
35 | else | |
36 | WARN(1, "double list_add attempt detected in net %x %s\n", | |
37 | net->ns.inum, (net == &init_net) ? "(init_net)" : ""); | |
af558e33 BF |
38 | spin_unlock(&grace_lock); |
39 | } | |
40 | EXPORT_SYMBOL_GPL(locks_start_grace); | |
41 | ||
42 | /** | |
43 | * locks_end_grace | |
f7790029 | 44 | * @net: net namespace that this lock manager belongs to |
af558e33 BF |
45 | * @lm: who this grace period is for |
46 | * | |
47 | * Call this function to state that the given lock manager is ready to | |
48 | * resume regular locking. The grace period will not end until all lock | |
49 | * managers that called locks_start_grace() also call locks_end_grace(). | |
50 | * Note that callers count on it being safe to call this more than once, | |
51 | * and the second call should be a no-op. | |
52 | */ | |
f7790029 JL |
53 | void |
54 | locks_end_grace(struct lock_manager *lm) | |
af558e33 BF |
55 | { |
56 | spin_lock(&grace_lock); | |
57 | list_del_init(&lm->list); | |
58 | spin_unlock(&grace_lock); | |
59 | } | |
60 | EXPORT_SYMBOL_GPL(locks_end_grace); | |
61 | ||
003278e4 | 62 | static bool |
c87fb4a3 | 63 | __state_in_grace(struct net *net, bool open) |
af558e33 | 64 | { |
f7790029 | 65 | struct list_head *grace_list = net_generic(net, grace_net_id); |
c87fb4a3 | 66 | struct lock_manager *lm; |
db9c4553 | 67 | |
c87fb4a3 BF |
68 | if (!open) |
69 | return !list_empty(grace_list); | |
70 | ||
71 | list_for_each_entry(lm, grace_list, list) { | |
72 | if (lm->block_opens) | |
73 | return true; | |
74 | } | |
75 | return false; | |
76 | } | |
77 | ||
809d4fcf CL |
78 | /** |
79 | * locks_in_grace | |
80 | * | |
81 | * Lock managers call this function to determine when it is OK for them | |
82 | * to answer ordinary lock requests, and when they should accept only | |
83 | * lock reclaims. | |
84 | */ | |
003278e4 | 85 | bool locks_in_grace(struct net *net) |
c87fb4a3 | 86 | { |
003278e4 | 87 | return __state_in_grace(net, false); |
af558e33 BF |
88 | } |
89 | EXPORT_SYMBOL_GPL(locks_in_grace); | |
f7790029 | 90 | |
003278e4 | 91 | bool opens_in_grace(struct net *net) |
c87fb4a3 | 92 | { |
003278e4 | 93 | return __state_in_grace(net, true); |
c87fb4a3 BF |
94 | } |
95 | EXPORT_SYMBOL_GPL(opens_in_grace); | |
96 | ||
f7790029 JL |
97 | static int __net_init |
98 | grace_init_net(struct net *net) | |
99 | { | |
100 | struct list_head *grace_list = net_generic(net, grace_net_id); | |
101 | ||
102 | INIT_LIST_HEAD(grace_list); | |
103 | return 0; | |
104 | } | |
105 | ||
106 | static void __net_exit | |
107 | grace_exit_net(struct net *net) | |
108 | { | |
109 | struct list_head *grace_list = net_generic(net, grace_net_id); | |
110 | ||
b8722857 VA |
111 | WARN_ONCE(!list_empty(grace_list), |
112 | "net %x %s: grace_list is not empty\n", | |
113 | net->ns.inum, __func__); | |
f7790029 JL |
114 | } |
115 | ||
116 | static struct pernet_operations grace_net_ops = { | |
117 | .init = grace_init_net, | |
118 | .exit = grace_exit_net, | |
119 | .id = &grace_net_id, | |
120 | .size = sizeof(struct list_head), | |
121 | }; | |
122 | ||
123 | static int __init | |
124 | init_grace(void) | |
125 | { | |
126 | return register_pernet_subsys(&grace_net_ops); | |
127 | } | |
128 | ||
129 | static void __exit | |
130 | exit_grace(void) | |
131 | { | |
132 | unregister_pernet_subsys(&grace_net_ops); | |
133 | } | |
134 | ||
135 | MODULE_AUTHOR("Jeff Layton <jlayton@primarydata.com>"); | |
136 | MODULE_LICENSE("GPL"); | |
137 | module_init(init_grace) | |
138 | module_exit(exit_grace) |